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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2019-16215

The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2019-16215
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 10:36 UTC · Revision 1

Source evidence

CVE-2019-16215

core-osv · Original source

Published 18 Sept 2019, 12:15 UTC

The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.

osv:CVE-2019-16215
Complete source record
{
  "id": "c5016984538596f4ee2d9cdd2161065829f8cc24e51d03bbcce4538d000634a6",
  "url": "https://osv.dev/vulnerability/CVE-2019-16215",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2019-16215",
    "summary": "The Markdown parser in Zulip server before 2.0.5 used a regular expression vulnerable to exponential backtracking. A user who is logged into the server could send a crafted message causing the server to spend an effectively arbitrary amount of CPU time and stall the processing of future messages.",
    "evidence": "osv:CVE-2019-16215",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2019-16215",
      "aliases": [
        "CVE-2019-16215"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zulip/zulip",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2bb3af1ade5bb3613dc88d44164abbe1230cd679"
                },
                {
                  "fixed": "5797f013b3be450c146a4141514bda525f2f1b51"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.0.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5797f013b3be450c146a4141514bda525f2f1b51"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.0.4",
            "2.0.3",
            "2.0.2",
            "2.0.1",
            "2.0.0",
            "2.0.0-rc1",
            "1.9.0",
            "1.9.0-rc3",
            "1.9.0-rc2",
            "1.8.0",
            "1.8.0-rc1",
            "1.7.0",
            "1.6.0",
            "1.5.0",
            "1.4.0",
            "1.3.13",
            "1.3.11",
            "1.3.10",
            "1.3.9",
            "1.3.8",
            "1.3.7",
            "1.3.6",
            "1.3.5",
            "1.3.4",
            "1.3.3",
            "1.3.2",
            "1.3.1",
            "1.3.0",
            "enterprise-1.2.0",
            "enterprise-1.1.5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-16215.json"
          }
        }
      ],
      "modified": "2026-10-20T10:50:46.214965539Z",
      "provider": "osv",
      "references": [
        "https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/",
        "https://github.com/zulip/zulip/commit/5797f013b3be450c146a4141514bda525f2f1b51"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2019-16215",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 382131,
  "published_at": "2019-09-18T12:15:10.91+00:00"
}